Find in Library

A synthesis inversion based on the atmospheric zoom model TM5 is used to derive top-down estimates of CH₄ emissions from individual European countries for the year 2001. We employ a model zoom over Europe with 1&deg; &times; 1&deg; resolution that is two-way nested into the global model domain (with resolution of 6&deg; &times; 4&deg;. This approach ensures consistent boundary conditions for the zoom domain and thus European top-down estimates consistent with global CH₄ observations. The TM5 model, driven by ECMWF analyses, simulates synoptic scale events at most European and global sites fairly well, and the use of high-frequency observations allows exploiting the information content of individual synoptic events. A detailed source attribution is presented for a comprehensive set of 56 monitoring sites, assigning the atmospheric signal to the emissions of individual European countries and larger global regions. <P style='line-height: 20px;'> The available observational data put significant constraints on emissions from different regions. Within Europe, in particular several Western European countries are well constrained. The inversion results suggest up to 50-90% higher anthropogenic CH₄ emissions in 2001 for Germany, France and UK compared to reported UNFCCC values (EEA, 2003). A recent revision of the German inventory, however, resulted in an increase of reported CH₄ emissions by 68.5% (EEA, 2004), being now in very good agreement with our top-down estimate. The top-down estimate for Finland is distinctly smaller than the a priori estimate, suggesting much smaller CH₄ emissions from Finnish wetlands than derived from the bottom-up inventory. The EU-15 totals are relatively close to UNFCCC values (within 4-30%) and appear very robust for different inversion scenarios.